Dictyostelium discoideum as a Novel Host System to Study the Interaction between Phagocytes and Yeasts

Abstract

The social amoeba <i>Dictyostelium discoideum</i> is a well-established model organism to study the interaction between bacteria and phagocytes. In contrast, research using <i>D. discoideum</i> as a host model for fungi is rare. We describe a comprehensive study, which uses <i>D. discoideum</i> as a host model system to investigate the interaction with apathogenic (<i>Saccharomyces cerevisiae</i>) and pathogenic (<i>Candida</i> sp.) yeast. We show that <i>Dictyostelium</i> can be co-cultivated with yeasts on solid media, offering a convenient test to study the interaction between fungi and phagocytes. We demonstrate that a number of <i>D. discoideum</i> mutants increase (<i>atg1</i>^-, <i>kil1</i>^-, <i>kil2</i>^-) or decrease (<i>atg6</i>^-) the ability of the amoebae to predate yeast cells. On the yeast side, growth characteristics, reduced phagocytosis rate, as well as known virulence factors of <i>C. albicans</i> (<i>EFG1, CPH1, HGC1, ICL1</i>) contribute to the resistance of yeast cells against predation by the amoebae. Investigating haploid <i>C. albicans</i> strains, we suggest using the amoebae plate test for screening purposes after random mutagenesis. Finally, we discuss the potential of our adapted amoebae plate test to use <i>D. discoideum</i> for risk assessment of yeast strains.